写入parquet格式

Dataframe to file

#![allow(unused)]

fn main() {
use std::fs::File;
use polars::prelude::*;
let mut file = File::create("d:/output.parquet").expect("could not create file");
ParquetWriter::new(& mut file).with_compression(ParquetCompression::Zstd(None)).finish(& mut employee_df)?;
}

lazyframe to file

#![allow(unused)]
fn main() {
let mut opt = ParquetWriteOptions {
    compression: ParquetCompression::Zstd(None),//启用压缩
    maintain_order: true,//保持行顺序，默认多线程操作行序无法保证
    ..Default::default()
};
employee_df.lazy().sink_parquet("D:/output.parquet",opt)?;
}